{ Siberian Olympiad. 1 stage.
  Problemset: http://agul-problems1.googlecode.com/svn/trunk/2010-2011/wso/stage1/wso_1stage.pdf
  Problem 2
  Points: 100
}
var i,n:integer;  v,a,b,x1,y1,x2,y2,time,s,curtime:double;
begin
assign(input,'input.txt');
assign(output,'output.txt');
reset(input);
rewrite(output);
readln(n,v,a,b);
readln(x1,y1);
v:=v*1000;
time:=0;
for I := 2 to n do begin
  readln(x2,y2);
  curtime:=0;
  if y1=y2 then begin
    s:=x2-x1;
    curtime:=s/v;
  end else
  if y1<y2 then begin
    s:=sqrt(sqr(x2-x1)+sqr(y2-y1));
    curtime:=s/(a*v);
  end else
  if y1>y2 then begin
    s:=sqrt(sqr(x2-x1)+sqr(y2-y1));
    curtime:=s/(b*v);
  end;
  time:=time+curtime;
  x1:=x2;
  y1:=y2;
end;
writeln((time*60):0:5);
close(input);
close(output);
end.